Such a method is known from E. SARDON, A. RIUS, N. ZARRAOA: “Estimation of the transmitter and receiver differential biases and the ionospheric total electron content from Global Positioning System observations” Radio Science, vol. 29, no. 3, 1994, pages 577-586. In the known method, the instrumental phase biases of satellites and receivers are lumped together with the phase ambiguities to form cycle slipping phase biases. After estimating the cycle slipping phase biases, linear combinations of the satellite and receiver instrumental group delay biases are determined together with the ionospheric delay using a Kalman filter. Lumping the phase biases with the phase ambiguities means that K+R biases are mapped on K·R ambiguities, resulting in a loss of information.
Within the known method, the cycle slipping phase biases are determined using a method described in GEOFFREY BLEWITT: “An Automatic Editing Algorithm For GPS Data” Geophysical Research Letters, vol. 17, no. 3, March 1990, pages 199-202. In this method the cycle slipping phase biases are determined using a widelane combination of P-code pseudorange measurements and by determining the widelane bias by a recursive state estimator. For identifying cycle slips, the determined wide lane biases are searched for discontinuities. The cycle slip itself can be calculated by evaluating cycle slips in an ionospheric combination of phase measurements. It is further proposed to resolve undetected cycle slips by using ambiguity resolution techniques.
Precise point positioning with integer ambiguity resolution requires precise estimates of satellite phase, satellite code, receiver phase and receiver code biases. It is known that satellite biases are changing slowly over time, e.g. Ge et al. [1], Gabor and Nerem [2] and Laurichesse and Mercier [3] have observed changes in narrowlane biases of at most 5 cm within a day and of less than 1 mm within 30 seconds.
The known method nevertheless fails to provide the required precision.